"The memo was provided to The Monitor on the condition of anonymity because the information is not yet public.

"Troops are expected to enter the area gradually, building up to 1,000 after about a month, the memo said.

"The troops will join the Texas Department of Public Safety in its recent surge to combat human smuggling and drug trafficking amid the influx of mostly Central Americans illegally crossing the Rio Grande. Perry, Lt. Gov. David Dewhurst, and Texas House Speaker Joe Straus announced the $1.3 million per week effort last month."

The Chronicle quotes state Sen. Juan "Chuy" Hinojosa as saying that Perry briefed legislators representing the border region, before he made a formal announcement.

The paper also rounded up some of the reaction from across the state:

"'The children fleeing violence in Central America are seeking out Border Patrol agents. They are not trying to evade them. Why would Rick Perry send soldiers to confront these kids?' U.S. Rep. Joaquin Castro, D-San Antonio, said.

"Rep. Jeff Leach, R-Plano, took to social media with his reaction, tweeting: 'Glad to hear @GovernorPerry is calling up the National Guard to help secure the border and protect our state. Pray for our troops.'"

"If the federal government does not do its constitutional duty to secure the Southern border of the United States, the state of Texas will do it," Perry said.

The paper adds that sending the National Guard to the border has precedent:

"Following the murder of Arizona rancher Robert Krentz in 2010, New Mexico Gov. Bill Richardson (D) ordered the National Guard to patrol the border to protect New Mexico residents. ...

"Obama sent the guard to the border in 2010 to support the Border Patrol. In 2006, Bush, in response to requests for support enforcing federal immigration laws from the governors of Arizona, California, New Mexico and Texas, sent some 6,000 National Guard troops to the Southern border for the same reason."

Meanwhile in Washington, President Obama will meet with the presidents of Guatemala, Honduras and El Salvador at the White House on Friday.

"The four leaders and Vice President Biden will discuss how to reinforce our ongoing collaboration to stem the flow of undocumented migrants from Central America to Mexico and the United States," the White House said in a statement. "This will include discussion of how the United States and Central American governments are cooperating to promote safe, legal, and orderly migration between our countries in a spirit of shared responsibility, including with respect to the return of family units, which began this week for all three countries."